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8/12/2019 E_div-12-Superior Performance Asphalt Pavement
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DIVISION 12 SUPERIOR PERFORMANCE ASPHALT PAVEMENT 325
12.1 Preface 325
12.2 Description 328
12.3 Materials 32812.3.1 Asphalt Materials 328
12.3.2 Aggregate 330
12.3.2.1 Quality Requirements For Combined Aggregate 331
12.3.2.2 Gradation Of Total Aggregate 332
12.4 Mix Design 335
12.4.1 Job-Mix Formula Requirements 336
12.4.2 The Design Job-Mix Formula 336
12.4.3 Procedures For Acceptance Of Job-Mix Formula 337
12.5 Construction 337
12.6 Traffic Control 338
12.7 Works Acceptance 338
12.7.1 Quality Control 339
12.7.2 Quality Assurance 339
12.8 Measurement and Payment 341
EXIT
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General Specifications of Urban Roads Construction Division 12-Superior performance asphalt pavement
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DIVISION 12
SUPERIOR PERFORMANCE ASPHALT PAVEMENT
12.1 Preface:
Design of Superior Performance Asphalt Pavements (Superpave) has been
developed on the basis of intensive research conducted to limit failures and distresses in
asphalt pavements during different stages of their service life. Superpave (which will be
defined later in this specification as the superior performance pavements) is an
abbreviation to SUperior PERformance Asphalt PAVEment.
Superpave system consists of requirements and specified methods for selection
of asphalt binder and aggregates which shall be met in the design and construction of
superior performance pavement layers. The Superpave system also consists of the
asphalt mix design method in three levels; the first level is defined as the volumetricdesign in addition to tests for determination of performance in the second and third
levels which are still in the development phase.
The Superpave specifications depend on the environmental factors, layer
location from pavement surface and actual traffic volume on the road.
The physical characteristics of the asphalt binder, which directly affect its performance
in the road, are measured by a series of specified tests at temperatures which simulate
the maximum and minimum temperatures to which the asphalt binder is subjected to
during mixing, spreading, compaction and service (pavement service life). Table
(12.2.1) shows these tests which are used to determine the type of the asphalt binder on
the basis of performance grade (PG). The identification consists of suffix numbers to
these two letters (PG) indicating the maximum and minimum temperatures within
which the asphalt binder is expected to perform satisfactorily. For example the grade
PG76-10 is expected to resist rutting at maximum temperature of seventy six (76)
degree Celsius and resist thermal cracking at minimum temperature of minus ten (-10)
degree Celsius.
The real difference between the specifications of Superpave and the traditional
specifications (penetration and viscosity) is in the performing of tests at different
temperatures, which suit the operational conditions of the project, in order to obtain the
target value in the specifications instead of fixing the test temperature and changing thatvalue.
Tests on asphalt binder or on asphalt mix are performed at temperatures
simulating those to which the asphalt mix is subjected during the pavement service life
and the behavior or performance of the asphalt binder depends on the temperatures and
the prolonging or shortening of the traffic loading period.
The Superpave combined these two factors loading period and temperature- by their
mutual effect on the asphalt binder and the asphalt mix where the slow loading rate is
simulated by the high temperatures and the quick loading rate by the low temperatures.
The specifications of the Superpave require obtaining records of temperatures inthe project area for twenty (20) years for determination of the adequate performance
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General Specifications of Urban Roads Construction Division 12-Superior performance asphalt pavement
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grade, where the minimum daily temperature and the maximum seven days average
temperature shall be determined during the approved monitoring period in the General
and/or Special Specifications.
Table 12.2.1: Asphalt Binder Tests
No. Test Aim
1Rolling Thin Film Oven Test
(RTFO)
Simulation of short term aging of asphalt
binder (< two years)
2 Pressurized Aging Vessel (PAV)Simulation of long term aging of asphalt
binder (>seven years)
3 Dynamic Shear Rheometer (DSR)
Measurement of asphalt binder
characteristics at intermediate and higher
temperatures
4 Rotational Viscosity (RV) Measurement of asphalt bindercharacteristics at higher temperatures
5 Bending Beam Rheometer (BBR)
6 Direct Tension Tester (DTT)
Measurement of asphalt binder
characteristics at lower temperatures
The adequate performance grade or type of the asphalt binder for the project
area is determined according to the following steps:
1- Determination of the minimum pavement temperature using the minimum airtemperature in the monitored period or by applying the following formula:
Low, Tpav= - 1.56+0.72Tair 0.004Lat2+6.26 Log10(H+25) - Z (4.4+0.52air
2)0.5
Where;
Tpav= Minimum pavement design temperature, C at H mm depth from the
surface.
(minimum expected pavement temperature degree during the design
period.Tair = Minimum daily air temperature, C
Lat = Geographical location of the project (latitude) in degrees.Z = Reliability factor = 2.055 at reliability 98 %
H = depth to the surface.
air = standard diviation of minimum airdaily temperature.
2- Determination of the maximum pavement temperature as the temperature at adepth of twenty (20) millimeters from the pavement surface, which is
determined from approved mathematical formulas by using the average air
temperature for the hottest seven days during the monitoring period and the
geographical location of the project (latitude), using the following equation :
High, Tpav =54.32+0.78Tair0.0025Lat2
-15.14 Log10(H+25)+Z (9+0.61air2
)0.5
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General Specifications of Urban Roads Construction Division 12-Superior performance asphalt pavement
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Where;
Tpav= Maximum pavement design temperature at H mm depth from pavement
surface, C.
Tair = Average hottest seven days air temperature, C.
Lat = Geographical location of the project (latitude) in degrees.
Z = Reliability factor = 2.055 at reliability 98 %H = depth to the surface.
air = standard deviation of maximum seven day airtemperature.
3- The reliability used in determination of the maximum or minimum temperatureshall not be less than ninety eight (98) percent. This implies increasing the
average maximum temperatures and decreasing the average minimum
temperatures by twice the standard deviation value of the average temperatures
for twenty years period.
The aggregate plays an important role in the performance of asphalt mixes at
high temperatures and high humidity. This role is less important at low temperatures infatigue cracking and low thermal cracking problems. The characteristics of aggregates
are classified in the Superpave specifications into three groups as follows:
1- Consensus Properties: Consensus properties are used for determination of theangularity of the fine and coarse aggregate grains and the degree of fracture and
number of fractured faces and are considered as one of the important factors in
obtaining the required performance of the asphalt mix. Specific requirements in
these properties shall be satisfied on the basis of traffic volume and location of
the layer from pavement surface. These properties are :
- Coarse Aggregate Angularity- Fine Aggregate Angularity- Flat and Elongated Particles- Clay content
2- Source Properties: Source properties are used in judgment of suitability of thesource of aggregates used in production of the Superpave, for its importance in
quality assurance. These properties include the following:
- Toughness- Soundness-
Deleterious Materials
3- Gradation Properties: Superpave has developed methodology for determinationof aggregate gradation in asphalt mixes by considering the gradation curve of
sieve sizes raised to the power 0.45. This curve consists of a straight line joining
the point of the 100% passing at the maximum size and the zero point, called the
maximum density line. Two additional properties have been added to the
maximum density line, which are :
- Control Points.- Restricted Zone.
Control points are upper and lower limits for the percentage passing fromdefinite sieves. These Sieves are the maximum size, the maximum nominal size, the
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General Specifications of Urban Roads Construction Division 12-Superior performance asphalt pavement
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intermediate size 2.36 mm and the minimum size 0.075 mm. The control point value in
each sieve differs by the variation of the maximum nominal size of the aggregate. The
restricted zone is a zone where the gradation curve is not recommended to pass through,
since the gradation passing through this zone will have insufficient voids in the mineral
aggregate (VMA) and is considered to be highly sensitive to any increase or decrease in
asphalt content.
The aggregate gradation selected for Superpave is known as the Design
Aggregate Structure and should preferably pass below the restricted zone.
The performance of the asphalt mixes is determined from series of tests on
prepared laboratory specimens using gyratory compactor and by measurements of the
volumetric properties which include air voids, voids in the mineral aggregate and voids
filled with asphalt and then use these properties and measurements in performance
models for estimation of the number and shape of pavement distresses on the basis of
time and traffic factors.
12.2 Description:
This section includes provision of the asphalt binder which satisfies the required
performance specifications for the project area and selection of the suitable aggregate in
terms of gradation and quality requirements for production of an asphalt mix which
satisfies the performance requirements and design conditions stated in the this General
or Special Specifications and hauling , spreading and compacting the mix for
construction of the superior performance asphalt pavement layers in accordance with
the plans , Special Specifications , contract documents and this General Specifications .
12.3 Materials:
12.3.1 Asphalt Materials:
The asphalt materials used in the Superpave consist of the modified or unmodified
asphalt binder which shall satisfy the quality requirements shown in Table (12.3.1) of
this general Specification. Unless otherwise defined in the contract documents or in
the Special Specifications, the contractor shall submit a study, prepared by a specialized
authority, which shows the suitable performance grade of the asphalt binder for the
project area.
The performance grade shall be determined according to the sequence followed in
the standard AASHTO PP-6 The Standard Method of Approving the Suppliers Gradeof the Asphalt Binder and Specifications of Performance grade of the Asphalt Binder
AASHTO MP-1 standard.
The performance grade of the asphalt binder shall be selected on the basis of
temperatures of the project location in any zone in the Kingdom, using the equations in
item 12.1 of this division and in case there is no information about the project the
performance grade shown in Figure (12.3.1) Temperature Zones of the Kingdom shall
be use. This selected grade shall be increased by the performance degrees shown in
Table (12.3.2), according to the speed and the design traffic volume in ESALs in the
design lane for twenty (20) years. The properties of the selected asphalt binder shall
conform to the requirements shown in Table (12.3.1).
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When the available asphalt binder does not satisfy the performance
requirements, the Contractor shall modify the asphalt binder by using one of the
approved and common modifiers (Polymers) in the Kingdom. He shall also submit
technical report, prepared by specialized authority, showing the proposed polymer type,
its percentage, method of addition and test results which verify the satisfaction of the
asphalt binder type to the quality requirements shown in Table (12.3.1).
Table 12.3.1: Quality Requirements of Performance Grades of Asphalt Binder
Test Description Specification Requirements
New Asphalt
Flash point AASHTO T-248 2300C (min)
Rotational Viscosity At 1350C
AASHTO
TP-483 Pa.sec (max)
Dynamic Shear (DSR)G*/sinat 10 rad /sec
At the highertemperature
AASHTOTP-5
1 kPa (min)
Specimens of Asphalt Residue from RTFO
% loss (RTFO) At 1630C
AASHTO T-
2401% (max)
Dynamic Shear (DSR),
G*/sin
At the higher
temperature
AASHTO
TP-52.2 kPa (min)
Specimens of Asphalt Residue from RTFO and PAV
Dynamic Shear (DSR),
G*sin
At the median
temperature *
AASHTO
TP-5
5000 kPa
(max)
CreepStiffness (S)
At minimumtemperature +10
C for 60 sec
AASHTOTP-1
300 Mpa (max)Bending
Beam
Rheometerm-value
At minimum
temperature +10
C for 60 sec
AASHTO
TP-10.3 (min)
Direct Tension At minimum
temperature
AASHTO
TP-31% (min)
*NOTE: see Table 1 in Appendix 2.
Table 12.3.2: Increase of Performance Degree of Asphalt Binder on the Basis of
Traffic Volume and Speed
Increase of Performance Degree According to Traffic SpeedDesign Traffic
Volume
(million ESALs)70 kph
< 0.3 No need
0.3 -
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Figure 12.3.1: Temperature Zones of the Kingdom
The selected performance grade shall be modified on the basis of climate
temperature in the project area in accordance with Section 12.2 or as determined from
Figure (12.3.1), by increasing the maximum temperature only by the amount of the
performance degrees shown in Table (12.3.2) (each performance degree equals six (6)
degrees Celsius), according to the speed and design volume of traffic on the road. The
minimum temperature in the performance grade shall not be modified. For example, ifthe selected performance grade for a project, according to the pavement temperature, is
PG70-10 and the design traffic speed is greater than seventy (70) kph and the design
traffic volume is between ten (10) to thirty (30) million ESAL in the design lane, the
performance grade of the asphalt binder shall be increased one degree to be of the type
PG76-10.
The Contractor shall use modified asphalt binder in construction of Superpave
asphalt concrete according to the ministry request in any of the Kingdom zones and
taking into consideration that the performance degree of that asphalt binder is increased
according to traffic volume and speed in the target project as shown in figure (12.3.1)and Table (12.3.2). The contractor has the right to request about the modification cost if
it is not mentioned in the contract documents, but if the ministry does not request that
and it is not mentioned in the contract documents the Contractor has no right to claim
any additional compensation accordingly.
12.3.2 Aggregate:
The aggregate used in production of Superpave shall meet all stated
requirements in this section of the General Specification, unless otherwise stated in the
Special Specifications. The Contractor shall, at his own responsibility, define the
source(s) and the aggregate quantities suitable for work in accordance with the
requirements of this General Specifications or the Special Specifications.
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General Specifications of Urban Roads Construction Division 12-Superior performance asphalt pavement
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The different aggregate sizes shall be stockpiled on stable clean leveled surface
and in spaced heaps of not less than ten (10) meters apart or in wall-separated heaps.
The aggregates shall be hauled from stockpiles locations by equipments which are
approved by the Engineer. The hauling and/or stockpiling method shall not lead to
pollution of the environment or aggregate or particle segregation.
The Contractor is allowed to use up to 15% by weight of total aggregates of non
fractured fine aggregate for production of Superpave, provided that the total mix of the
fractured and non fractured fine aggregate shall conform to the fine aggregate angularity
which is based on the uncompacted air voids of this General Specifications or the
Special Specifications.
The mineral filler used in Superpave shall be a product of rock powder or rock
dust with plasticity index not more than 4%. It may also be of furnace slag and/or metal
raw or Portland cement or hydrated lime or any other material which will satisfy the
quality requirements as in AASHTO M-85 or AASHTO M-240 for Portland cement and
ASTM C 207 for hydrated lime.
12.3.2.1 Quality Requirements for combined Aggregate:
The combined aggregate shall satisfy all consensus properties shown in Table
(12.3.3), and the flat and elongated particles test shall be performed on materials
retained on sieve 4.75 mm while the percent of air voids test on the uncompacted fine
aggregate shall be performed on materials passing sieve 2.36 mm, according to the
method defined in the above mentioned Table.
Not contradicting the Special Specifications, the source properties of the
aggregate used in Superpave production, shall conform to all requirements listed in
Table (12.3.4), according to the defined test method.
All tests listed in Tables (12.3.3) and (12.3.4) of this General Specifications
shall be performed on the blended aggregate which is selected for production of
Superpave concrete, except the Los Angeles Abrasion Test which may be performed on
the blended aggregate or for each source / stockpile alone.
Table 12.3.3: Aggregate Consensus Properties Requirements
Coarse Aggregate
Angularity
(At least %)
Percent of Air Voids in
fine Aggregate (passing
4.75 mm sieve)
(At least %)
Layer Location from Pavement Surface*
Design
TrafficVolume
(ESAL)
(million)
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Table 12.3.4: Requirements of the Aggregate Source Properties
Aggregate Properties Test Method Requirements %
Los Angeles Abrasion
(max)AASHTO T-96 40
Soundness (loss in SodiumSulphate) (max)
AASHTO T-104 20
Clay lumps and friable
particles (max)AASHTO T-112 0.25
12.3.2.2 Gradation of Total Aggregate:
The combined aggregate of Superpave shall satisfy one of the gradation
requirements shown in Tables from (12.3.5) to (12.3.9) which is classified according to
the nominal maximum size of the aggregate.
The percent of aggregate used in the asphalt mix shall be determined by the useof the average gradation results of five representative and independent samples taken
from each stockpile and/or cold bins and/or hot bins, and at least three trials shall be
performed for different gradations within the specification limits of the approved
gradation for each Superpave mix in order to determine the design aggregate structure
and the percentages of the different aggregate sizes.
Satisfaction of the aggregate sizes to quality and gradation requirements shall be
checked whenever the source and /or method of fracture change. The maximum
nominal size shall not be greater than half the pavement layer thickness.
Table 12.3.5: Gradation of combined Aggregate
(Maximum Nominal Size is 9.5 mm)
Control Points (%) Restricted Zone (%)Sieve
Size
(mm)Minimum Maximum Minimum Maximum
Target
Design
Values*(%)
Tolerance
Limits (%)
12.50 100 - - - - -
9.50 90 100 - - - -
4.75 - 90 - - * 6
2.36 32 67 47.2 47.2 * 6
1.18 - - 31.6 37.6 - -
0.600 - - 23.5 27.5 * 4
0.300 - - 18.7 18.7 * 3
0.150 - - - - - -
0.075 2 10 - - * 2
* represents target values which the Contractor shall determine during the asphalt mix design to thenearest
0.1% , and tolerance limits shown are the permissible deviation from target values.
** It is better if the total gradation avoid the restricted zone and that according to the engineer acceptance.
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Table 12.3.6: Gradation of combined Aggregate
(Maximum Nominal Size is 12.5 mm)
Control Points (%) Restricted Zone (%)Sieve Size
(mm) Minimum Maximum Minimum Maximum
TargetDesign
Values*(%)
Tolerance
Limits (%)
19 100 - - - -
12.50 90 100 - - - -
9.50 90 - - - -
4.75 - - * 6
2.36 28 58 39.1 39.1 * 6
1.18 - - 25.6 31.6 - -
0.600 - - 19.1 23.1 * 4
0.300 - - 15.1 15.1 * 3
0.150 - - - - - -0.075 2 10 - - * 2
* represents target values which the Contractor shall determine during the asphalt mix design to thenearest
0.1% , and tolerance limits shown are the permissible deviation from target values.** It is better if the total gradation avoid the restricted zone and that according to the engineer acceptance.
Table 12.3.7: Gradation of combined Aggregate(Maximum Nominal Size is 19 mm)
Control Points (%) Restricted Zone (%)Sieve
Size
(mm)Minimum Maximum Minimum Maximum
Target
Design
Values*(%)
Tolerance
Limits (%)
25 100 - - - - -
19 90 100 - - - -
12.50 - 90 - - - -
9.50 - - - - - -
4.75 - - - - * 6
2.36 23 49 34.6 34.6 * 61.18 - - 22.3 28.3 * -
0.600 - - 16.7 20.7 * 4
0.300 - - 13.7 13.7 * 3
0.150 - - - - - -
0.075 2 8 - - * 2
* represents target values which the Contractor shall determine during the asphalt mix design to the
nearest0.1% , and tolerance limits shown are the permissible deviation from target values.
** It is better if the total gradation avoid the restricted zone and that according to the engineer acceptance.
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Table 12.3.8: Gradation of combined Aggregate
(Maximum Nominal Size is 25 mm)
Control Points (%) Restricted Zone (%)Sieve
Size(mm)
Minimum Maximum Minimum Maximum
Target
DesignValues*(%)
Tolerance
Limits (%)
37.5 100 - - - - -
25 90 100 - - - -
19 - 90 - - - -
12.50 - - - - - -
9.50 - - - - - -
4.75 - - 39.5 39.5 * 6
2.36 19 45 26.8 30.8 * 6
1.18 - - 18.1 24.1 * -
0.600 - - 13.6 17.6 * 4
0.300 - - 11.4 11.4 * 3
0.150 - - - - - -
0.075 1 7 - - * 2
* represents target values which the Contractor shall determine during the asphalt mix design to the
nearest0.1% , and tolerance limits shown are the permissible deviation from target values.
** It is better if the total gradation avoid the restricted zone and that according to the engineer acceptance.
Table 12.3.9: Gradation of combined Aggregate(Maximum Nominal Size is 37.5 mm)
Control Points (%) Restricted Zone (%)Sieve Size
(mm) Minimum Maximum Minimum Maximum
Target
Design
Values*(%)
Tolerance
Limits (%)
50 100 - - - - -
37.5 90 100 - - - -
25 - 90 - - - -
19 - - - - - -
12.50 - - - - - -
9.50 - - - - - -
4.75 - - 34.7 34.7 * 6
2.36 15 41 23.7 27.3 * 6
1.18 - - 15.5 21.5 *
0.600 - - 11.7 15.7 * 4
0.300 - - 10 10 * 3
0.150 - - - - - -
0.075 0 6 - - * 2
* represents target values which the Contractor shall determine during the asphalt mix design to thenearest
0.1% , and tolerance limits shown are the permissible deviation from target values.
** It is better if the total gradation avoid the restricted zone and that according to the engineer acceptance.
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12.4 Mix Design:
Design of superior performance asphalt mix shall be in accordance with the
Asphalt Institute method shown in Superpave Series No. 2 (SP-2) Mix Design of
Superpave Asphalt concrete. The Appendix (2) of this General Specifications shows an
example of Superpave volumetric mix design method.
The design steps of the asphalt mix, as in level one of the superior performanceasphalt pavement mix Design by the Volumetric Method, include the following:
1- Selection of the asphalt binder which satisfies the approved requirements as initem 12.3.1 of this Specification.
2- Selection of the aggregate which satisfies the specifications of the definedsource and consensus properties and meets the required gradation according to
the maximum nominal size by performing three different trail blends and
comparing them with the combined gradation requirements.
3- Estimation of the preliminary optimum asphalt binder content for each blend.4- Determination of the temperature range for each of the mixing and compaction
by performing the Rotational Viscosity test as in AASHTO TP-48 such that the
suitable mixing viscosity of the asphalt binder will in the range of (0.17 0.02)and for compaction will be in the range (0.28 0.03) Pa.sec .
5- Selection of the optimum asphalt binder content as follows:- Mixing asphalt with the different aggregate blends and heating (aging)
the mix in the oven at compaction temperature specified by rotational
viscosity test for two hours if the aggregate absorption does not exceed
2% and for four hours if the absorption exceeding this value, then
compacting the specimens by the gyratory compactor as in AASHTO
TP-4 method, The Standard Method for Preparation and Determination
of the Specific Gravity of Compacted Specimens by the Gyratory
Compactor.
- Analysis of the volumetric properties of the compacted mix andcomparing them with the volumetric properties as in Superpave system
and selection of the best results as design aggregate structure according
to the specification AASHTO PP-19 The Standard Volumetric Analysis
Method for Compacted Hot Mix.
- Compaction of specimens from the design aggregate gradation withdifferent asphalt contents, plotting the asphalt binder versus the air voids
in the compacted specimens curve and determination of the design
asphalt binder content at four (4) percent air voids.
- Determination of the volumetric properties using the optimum asphaltcontent from the plotted curves of; asphalt binder content versus thevolumetric properties of the asphalt mix (Voids in the Mineral
Aggregate (VMA), Voids Filled with Asphalt (VFA), density at initial
(Nini), design (Ndes) and maximum (Nmax) compaction levels and then
comparison with the requirements of the volumetric properties shown in
Table (12.4.2).
6- Evaluation of the resistance of the selected asphalt mix to water effect
according to AASHTO T-283 method.
Table (12.4.1) shall be considered as guidelines for the selection of the required
compaction level in the laboratory for the asphalt mix on the basis of the design traffic
volume in EASLs in the design lane for twenty (20) years.
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Table 12.4.1: Superpave Compaction levels
No of gyrations
Maximum Design Initial
Design
ESAL
(million) Nmax Ndes Nini
Road Class
< 0.3 75 50 6 Residential0.3 - < 3 115 75 7 Collector
3 - < 30 160 100 8Expressway Arterial / Industrial
Regions
30 205 125 9Expressway / Truck Parking /
Decent Lanes / Intersections
12.4.1 Job-Mix Formula Requirements:
The asphalt binder shall satisfy the quality requirements shown in Table
(12.3.1), and the Contractor shall define and verify the target values of the gradation of
the total aggregate of the Superpave within the allowed limits shown in Table (12.3.5)
or Table (12.3.6) or Table (12.3.7) or Table (12.3.8) Table or (12.3.9) according to the
nominal maximum size of the aggregate provided that the quality requirements shown
in Tables (12.3.3) and (12.3.4) shall be satisfied. The asphalt mix shall also satisfy the
volumetric properties shown in Table (12.4.2).
The ratio of the average tensile resistance of the compacted specimens subjected
to environmental conditioning to average tensile resistance of the compacted specimens
not subjected to environmental conditioning shall not be less than seventy five (75)
percent as determined by AASHTO T-283 test Resistance of the compacted
bituminous Mixture to moisture induced Damages.
Table 12.4.2: Requirements of the Volumetric Properties of Superpave
Voids in the Mineral
Aggregate (VMA)
(at least %)
Ratio of Required
Density to Maximum
Theoretical Density
(%Gmm) Nominal Maximum Size
(mm)
ESALs
(million)
Nmax Ndes Nini 9.5 12.5 19 25 37.5
Voids
Filled
with
Asphalt
(VFA)
**
Ratio of
Percentage
Passing Sieve
0.075 mm to
Asphalt
Binder
Content *
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of materials used in the asphalt mix production, material proportions, original test
results of consensus properties, source properties required for aggregate materials which
proves conformity with the specified requirements and the original test results of the
designed asphalt mix in the laboratory which shall include; gradation, specific gravity
for aggregate sizes, test results of the asphalt binder, grade, type and percentages of
used modifiers, mixing method, plant location and test results of plant production.
12.4.3 Procedures for Acceptance of Job-Mix Formula:
The job-mix formula furnished by the Contractor shall be revised by the
ministry and shall be accepted or retuned to the Contractor for modifications within two
weeks. The Contractor shall prepare once again and resubmit to the ministry, for
approval, a new job-mix formula which will satisfy the specified requirements. The
Contractor shall not change sources or aggregate production methods or asphalt material
mixing after approval of the job-mix except after repeat of material testing and
submission of new mix.
12.5 Construction:Unless otherwise stated in the Special Specifications or otherwise conflicting
with what is listed in this section, the construction requirements shown in item 8.5.6
Construction shall be applied to the items related to preparation of asphalt materials,
aggregates, asphalt concrete mix and joint.
The Contractor shall ensure surface preparation (any type) on which Superpave
mix will be placed. He shall clean the surface from dust, loose material and any foreign
material and apply tack coat or prime coat by the method and equipment approved by
the Engineer and in accordance with the requirements listed in this General
Specifications and the Special Specifications. The Contractor shall also fill the cracks
and patch potholes if the surface is asphalt concrete, as shown in plans and contractdocuments. The central plants used in Superpave production, shall satisfy the
requirements listed in the specification AASHTO M 156 designation for the
"Requirements of Hot Mix Asphalt Plants.
The Contractor shall haul, place and spread the Superpave asphalt concrete to
the thickness specified in plans and by the manner and equipments stated in the Special
Specifications and this General Specifications. The asphalt mix temperature during
discharge from the plant into the truck shall not be less than one hundred and sixty
(160) degrees Celsius and not greater than one hundred and eighty (180) degrees
Celsius.
All Superpave layers shall be spread and initially compacted, in the initial
coverage, in temperatures not less than one hundred and thirty five (135) degrees
Celsius. All compaction works shall be finished before the mix temperature is reduced
to less than ninety (90) degrees Celsius. The compaction shall be in the form of
consecutive or sequential passes by approved rollers. The pass is defined as the
movement of one roller in any direction. The number of passes which cover the full
width of pavement by compaction is defined as the coverage. Table (12.5.1) may be
used as guidelines for determination of the degree of compaction, roller type and
number of coverage's.
Longitudinal joints shall be compacted first, and then compaction may be started
at the lower side towards the higher side (road center line) using self propelled steel or
pneumatic rollers. The weight of each of these rollers shall not be less than ten (10) tons
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and the Contractor shall take care of these rollers, maintain and operate in the manner
which will lead to the required purpose.
Table 12.5.1: Degree of Compaction and Number of Coverage
First Alternative Second AlternativeDegree ofCompaction Roller Type
Number of
Coverage **Roller Type
Number of
Coverage **
Initial Steel Roller 1 Vibratory Roller 1
Intermediate Pneumatic Roller 4 Vibratory Roller 2 4 *
Final Steel Roller 1 - 3 Steel Roller 1 - 3
* Depends on Roller Weight** The number of coverages shall be selected on the basis of the experimental section.
The number of tires of the pneumatic roller shall not be less than seven tires and the tires shall becapable of applying an air pressure of 258 kg/cm2 or ninety (90) pounds / square inch. The air
pressure in any tire shall not vary by more than 14 kg/cm2or five (5) pounds / square inch from the
approved pressure and the weight of each tire shall not be less than 2222 Kilograms or five thousand(5000) pound.
The longitude and latitude joints shall be compacted first, after that compaction
start from edges to the road axis using mechanical steel or pneumatic rollers and their
weights must not be less than ten (10) tons and the contractor shall operate, repair and
take care about it as to achieve its purpose.
The adequate number of rollers shall be provided and the compaction shall
continue till the required field density is reached. The compaction degree shall
determine on the basis of the experimental section results as in the standard method
AASHTO T-310 or the method AASHTO T-168. The degree of compaction shall not beless than 91% of the maximum theoretical density defined by the standard method
AASHTO T-209.
12.6 Traffic Control:
The Contractor shall take the effective measures to prevent all types of traffic
from using the Superpave layers unless approved by the Engineer and he shall take the
approval of the concerned authorities in this respect and follow the requirements shown
in item 8.5.7 of this General Specifications.
12.7 Works Acceptance:
Contractor shall apply quality control for superpave asphalt concrete productionby carrying out all the required arrangements to ensure that the used materials,
construction methods and the executed works achieve the quality requirements,
indicated in the standard specifications, special specifications, these general
specifications and other contract documents.
The Ministry shall apply the quality assurance works by verifying that the
contractor has carried out quality control procedures properly either through direct
supervision of the quality control procedures or by undertaking quality assurance
procedures neutrally on representative samples and with adequate numbers to judge the
execution and to decide in accepting or not accepting the completed work according to
the principles detailed in Division 17 of this general specifications except otherwisespecified in special specification or other contract documents.
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12.7.1 Quality Control:
The Contractor shall furnish a plan for the quality control system which he will
follow during the contract period at his own expense in his laboratories, as part of the
daily work follow up, or in other independent laboratories which are approved by the
ministry, thirty (30) days prior to commencement of the asphalt concrete production for
approval. The Contractor shall not start production and construction prior to obtainingwritten acceptance of the plan by the Engineer. He shall be committed to the plan during
the contract period. That plan shall include the number, qualifications of the work staff
and a list of devices, equipments, calibration methods, finished calibration certificates
from approved authority, number of available tests, and number of samples, their weight
and frequency.
The Contractor shall conduct the quality control tests for the materials at their
source, during use, when preparing the mix design and on the site as shown In Table
(12.7.1).
The total aggregate, including fine aggregate, mineral filler and asphalt binder,
shall conform to the approved proportions in the job mix formula within the allowedtolerances listed in item 12.3.2 of this General Specifications. When these percentages
are not conforming to the approved job mix formula within the allowed tolerances, the
mix production shall be suspended for recalibration.
At least two specimens from the produced asphalt mix shall be compacted by the
gyratory compactor as in AASHTO TP-4 method. And the maximum theoretical
specific density shall be performed for each mix intended for compaction in the
laboratory as in ASTM D 2041 method and according to the frequency stated in Table
(12.7.1) at the design compaction level (Ndes) in order to ensure that the volumetric
properties of the asphalt mix are within the following limits:
- The air voids and the voids in the mineral aggregate of the produced asphalt mixshall not vary by more than one (1) percent from what has been specified in the job
mix formula.
- The voids filled with asphalt shall not vary by more than five (5) percent from whathas been specified in the job mix formula.
- The ratio of the average tension resistance of the compacted and subjected toenvironmental conditioning specimens to the average tension resistance of the
compacted specimens, not subjected to environmental conditioning shall not be less
than seventy five (75) percent as determined by AASHTO T-283 test.
-
The gyratory compaction test shall be performed at the maximum compaction level(Nmax) for each four days production to ensure that the density ratio at this level of
compaction is less than ninety eight (98) percent of the maximum theoretical
specific density (Gmm).
12.7.2 Quality Assurance :
Ministry at any time has the right to assure the quality of materials and executed
works through carrying out or ordering others under its direct supervision to select
materials and check executed works for all or part of the quality control items specified
in 12.7.1 subsection.
Ministry has the right to review contractors quality control records and comparethese statistically with its results to insure quality according to what is specified in
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division 17 of these general specifications. It has the right to inspect the contractors
laboratory and its equipments, its technical staff, methods of testing and construction
method to insure the efficiency of the contractors technical staff and equipments and
compliance of his inspection methods, testing and construction method with the
approved methods.
Table 12.7.1: Quality control procedures for Superpave asphalt concrete mixes
Work Properties Testing method
Location
of
Sampling
Sampling frequency Requirements
Asphalt
binder
Quality requirements
and PG classification
Tests indicated in
Table 12.3.1
One test In the beginning ofsupply, during the mix design
and whenever the source or mixproperties are changed.
Table 12.3.1
Consensus propertiesTests indicatedin Table 12.3.3
Table 12.3.3
Source propertiesTests indicated in
Table 12.3.4
3 tests on different samples fromeach source at source approval
and design job mix formula orwhen source is changed or whennoticing a change in constructed
works properties, and 5 tests ondifferent randomly time selected
samples for each 5000 cubicmeters from each source during
construction.
Table 12.3.4Aggregate
Specific gravity (Gsb)and
absorption
AASHTO T-19
At
Source
3 samples during mix design andone test for each week or when
mix properties are changed.
Tables from12.3.5 to
12.3.9
Aggregate gradation
(dry mix)
AASHTO
T-27
3 samples during mix design and
one test for each week or whenmix properties are changed.
Tables from
12.3.5 to12.3.9
Specific gravity (Gsb)and
absorptionAASHTO T-19
3 samples during mix design andone test for each week or when
mix properties are changed.
Tables from12.3.5 to
12.3.9
Source propertiesTests indicated in
Table 12.3.4One test each month or whenmix properties are changed.
Table 12.3.4
Materials
during
construction
Consensus propertiesTests indicated
in Table 12.3.3
One test each month or when
mix properties are changed..Table 12.3.3
Aggregate gradationand asphalt content
AASHTO
T-27/T-164T-308/T-310
At least one samples for each for
each 500 cubic meters or one foreach daily production from each
constructed layer.
Tables from
12.3.5 toTables 12.3.9
Volumetric propertiesusing Gyratory
compaction at designnumber of Gyrations
(Ndes)
AASHTO TP-4
At least three tests at approval of
design aggregate structure orwhen properties or mix
aggregate are changed and one
test for each 500 cubic metersfrom each Plant or for each
working day which is the lesser.
Section 12.3and 2.4,
Table 12.4.1and 12.4.2
Percent of max density
Gmmusing Gyratorycompaction at
maximum number of
Gyrations (Nmax)
AASHTO TP-4
One Test for every four
production days or one test foreach 500 cubic meters from each
Plant which is the less
Table 12.4.2
Asphalt mix
tests
Maximum theoretical
specific gravity (Rice)
AASHTO
T-209/
ASTM D 2041
at
Stock Piles
At least three tests at approval of
design aggregate structure orwhen properties or mix
aggregate are changed and one
test for each 500 cubic metersfrom each Plant or for each
working day which is the lesser.
Item 12.7.1
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Mixture sensitivity tomoisture induced
damage
AASHTO
T-283
One test when design andapproval of job mix formula or
when the mix properties arechanged.
Item 12.7.1
Compaction ASTM D-2726
one test for each 1000 squaremeters from each constructedlayer or working day which is
the lesser.
Section 12.5
Thickness ASTM D-3549
One test from each 1000 square
meters from each constructedlayer or working day which is
the lesser.
Section 12.5
Skid resistance on
surface layer
Skid resistance
measurement
Skid measurements for each
working day.Section 12.5
Surface layer roughnessRoad roughness
measurement
Using measurement methods
indicated in specialspecifications for each working
day.
Section 12.5
Constructed
works
Levels, dimensions
and, slopes
measurements.
Contractdocuments
At site
Cross section measurements
each 25 meters or 5 sectionseach 1000 square meters
whichever is greater.
Requirements
stated incontract
documents
The requirements including in division seventeen (17) in these general
specifications shall apply to accept constructed superpave asphalt concrete works. On
application of the statistical system, the elements of pay factor determination shall
include; the thickness, gradation, surface smoothness, asphalt binder content and
compaction. The number of samples and the lot amount shall be as shown in Table
(17.3.1) of this General Specifications.
The quality assurance procedures shall be applied as shown in sub item 8.5.8.2and table (8.5.6), which is concerned with compaction requirements, thickness of the
constructed asphalt concrete - as decided on plans -, aggregate gradation, asphalt binder
content and evenness of the surface layer. The allowed tolerances limits for gradation
shall be as shown in Tables (12.3.5), (12.3.6), (12.3.7), (12.3.8) and (12.3.9), and the
asphalt binder content shall be in the range 0.4 % from the approved design content.
12.8 Measurement and Payment:
Each lot quantity of the Superpave concrete layer shall be measured in cubic
meters compacted to the specified density ratio and in accordance with the thickness
shown on plans. The payment shall be according to the contract unit price or the
modified unit price per cubic meter for any constructed layer of asphalt concrete. No
measurement shall be made for quantities and areas placed outside the allowed limits
for payment purposes. Payment and prices shall be full compensation against provision
of labor, materials, equipments, tools and all other items necessary for work completion
as shown in this General Specifications and this Special Specifications.
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